In recent years, in flat displays such as a liquid crystal display device, a stereoscopic image display device using stereoscopic images is known. One of the stereoscopic image display device uses a gradient index lenses such as a liquid crystal lens arranged in front of a display panel. By controlling alignment of liquid crystal molecules of a liquid crystal layer by impressing voltage, the liquid crystal lens functions so as to give a distribution of refractive index in the liquid crystal layer, and to make operate as a lens. The stereoscopic image display device is realized with the liquid crystal lens by having a right eye image displayed on the display device enter into a viewer's right eye, and having a left eye image enter in the viewer's left eye. Moreover, it is also possible to switchover between the two-dimensional display mode and the three-dimensional display mode by switching ON and OFF the impressed voltage to the liquid crystal lens.
Furthermore, in the case of the liquid crystal lens, it is also possible to operate a portion of the liquid crystal lens unit as a lens corresponding to a portion of the display device. Therefore, according to this structure, a partial three-dimensional display is possible in which the three-dimensional display is performed in an area of the display device while making the two-dimensional display in other areas.
In order to enable the partial three-dimensional display, it is necessary to form an alignment control electrode for carrying out alignment control of the liquid crystal molecules in an area of the liquid crystal lens, and to enable driving of the alignment control electrode formed in one area independently from other electrodes. Therefore, it is thought to provide a voltage supply electrode for carrying out voltage impressing to the alignment control electrode in a different layer from the alignment control electrode. However, in such structure, there is a possibility that electric field generated by the voltage supplied to the voltage supply electrode may affect the alignment of the liquid crystal molecule. If alignment change of the liquid crystal molecules arises, there is a possibility that distribution of refractive index may change from a desired distribution, and uneven coloring, etc., may be resulted by the voltage supply electrode at the time of the three-dimensional display.